The invention relates to a fluid actuated steering apparatus, particularly for use with an outboard motor on a marine vessel.
Outboard motors are a common form of propulsion for many marine vessels, and while direct mechanical steering is practical for low powered units, hydraulic steering is necessary for more powerful units.
All outboard motors have a generally vertical leg carrying a propeller, the leg being rotatable about a generally vertical axis which correspondingly swivels the propeller for steering, the axis being referred to as a steering axis. Commonly, hydraulic steering is effected by a hydraulic cylinder mounted generally transversely of a longitudinal axis of the vessel, the cylinder cooperating with a tiller arm so that actuation of the cylinder swivels the motor and propeller about the generally vertical axis to control steering.
In addition, most outboard motors are mounted for limited rotation about a generally horizontal axis, commonly called a tilt axis, by journalling the motor on a tilt rod or tilt tube. In this way the motor can be tilted between a lowered position thereof, in which the propeller is immersed in the water for propulsion, and a raised position in which the propeller can be positioned above the water for stowage, or partially lowered intermediate positions for use when the boat is in shallow or obstructed waters.
Several different arrangements of the hydraulic cylinder are possible, and in one common arrangement opposite ends of a piston rod of the steering cylinder are secured by linkages to opposite ends of a tilt rod or tilt tube. Such an arrangement has provisions for connecting the tiller to a portion of the steering cylinder to follow tilting movement of the outboard motor as it tilts between lowered and raised positions.
Two recent patents showing an arrangement of a horizontally disposed steering cylinder are U.S. Pat. Nos. 5,002,510 (inventor-Martin Rump) and 5,092,801 (inventor-James McBeth). Both of these structures show means for the tiller connection to accommodate tilting of the motor between the raised and lowered positions, which means are relatively complex and/or tend to introduce excessive lost motion into the connection. Other patents show alternative means of connecting the steering cylinder to the outboard motor, for example U.S. Pat. Nos. 4,773,882 (Inventor--Martin Rump) and 4,731,035 (Inventor--William Wagner).
In applicant's opinion, many of the tiller/cylinder connections in the prior art can be costly to manufacture and maintain, and can also present problems during installation of the steering apparatus.